Most plastic items these days are stamped or have printed on them a little triangle with a number inside it.  Of course, nobody really explains what these are except for maybe a way to divide plastics for recycling.

But there is more to them than that.  These numbers actually identify what kind of plastic the bottle or other item is made of.  Why is this important?  Some types of plastic material are quite toxic to the body, particularly our hormones. All plastic materials contain phthalates, which are chemicals used to soften and increase the flexibility of plastics and some tablet coatings, personal care products, building materials, detergents, and more.  It is considered a carcinogen.  This chemical will leach into whatever food or liquid is in the plastic container, especially when:

  • the plastic item gets warm via hot weather or the microwave
  • the plastic container is old - the amount of phthalates (plastic chemicals) that are released increases
  • the plastic container is very thin and flexible - the phthalates separate from the plastic container more easily

Another very worrisome chemical in some plastics is Bisphenol-A, or BPA.  Studies have shown this chemical to be a significant endocrine disruptor, that is, it alters or damages hormone function.  Many plastics manufacturers are now making BPA-free products, particularly baby bottles.  BPA can be found in plastics with a #3 or #7 on them.  Unfortunately the common substitutes for BPA, like BPS, BPF, BPB, and others, are just as toxic as BPA. That means they disrupt estrogen activity as much as BPA according to the following 2017 research paper: Society of Toxicology Article.

Below is a brief explanation of the numbers and letters that also sometimes appear on plastic material.  They are usually inside a triangle. Do not buy or use anything with a #3, 6 or 7 on them.  If you eat ready-made frozen meals, check the number of any plastic container the meal comes in, it may be a #7!

#1 - polyethylene terephthalate (PETE or PET). It’s ok, but don’t reuse bottles.

#2 - high density polyethylene (HDPE). This plastic is usually opaque.

#3 - polyvinyl chloride (PVC or V). Contains BPA - don’t use.

#4 - low density polyethylene (LDPE).

#5 - polypropylene (PP). Usually a harder, less flexible plastic.

#6 - polystyrene (PS), or Styrofoam. Readily leaches toxic phthalates - don’t use.

#7 - Mixed bag of “everything else.”  Frozen meals often use this plastic. May contain BPA - don’t use.